The present invention relates to a distributed operating system for controlling network elements in a data or telecommunication network.
For the network operator of telecommunication networks, it is becoming more and more important to be able to provide the network users with what are known as network services or integrated value-added services, in addition to simple basic services such as transmission of voice or data. What is meant by this is that the combination and enhancement of the basic services, for instance the unique number in different networks (Universal Personal Number, stationary and permanent networks), forwarding and answering machine functions in the network, and many others.
A known technical solution is an intelligent network, which is controlled centrally by a network element, that is known as the SCP (Service Control Point). This is described in the protocol suite Q. 12xx of the ITU.
A significant disadvantage of intelligent network technology is the strong dependency on the central network element in particular. The highly cost-intensive usage of high-performance and fail-safe hardware, on the one hand, and what are known as backup systems, on the other handxe2x80x94i.e. a doubling of the most important elements of the system (hardware and software),xe2x80x94is required in order to guarantee the necessary fail-safety in running operations.
It is the object of an invention to propose a solution as to how the network elements in an adaptive network architecture can be controlled and how value-added services can be provided network-wide and separately according to the provider. The above described disadvantages of the technology of intelligent networks should be avoided.
This and other objects are achieved by a distributed operating system controlled by a method connecting one or more higher ranking network elements in the network that provide network functions and services and providing that distributed network having system-independent interfaces, the distributed network integrating the network functions and services and basic services from lower ranking physical data networks via the one or more higher ranking network elements and making the network functions and services and basic services available to an upper most layer via the system independent interfaces.
The term physical base network refers to a homogenous network such as the telephone network (POTS) for the analog transmission of data such as speech, an ISDN network for digital transmission, the mobile telephone network, or the Internet, which is itself composed of individual networks.
A network operator is responsible for such a base network.
In the following comments, various terms are used for functions and services are described
a basic service is a basic service as provided to the user by the physical base network, potentially voice transmission in POTS, or the bearer services in ISDN;
a network function, on the other hand, is needed for operating a network and its services, though it is not directly visible to the user of network services. Traffic monitoring or routing belong to such functions, for example.
A network service is composed of basic services and possible enhancements (e.g. ISDN services).
An integrated value-added service is a network service that can be composed of network services even of different physical base network services. This can be provided by the network operator or by what is known as a service integrator as well.
An application refers to what is known as the application layer. Here the previously neutral network services and value-added services are adapted to the respective demand of the service provider and of the service user; such as, with respect to charging and tariff rating of services, for example
The communication with the physical base network is accomplished via the call of network functions, network services and basic services in the respective system-specific format. This refers to INAP (Intelligent Network Application Part), SS7(Signalling System No 7) or MAP (Mobile Application Part), for example.
A basic function is an additional function that is introduced by means of a new enhanced network architecture. It enables access to a physical base network or the distribution of the calls of the network services and functions that are distributed in the network, for example.
Neighboring network elements refers to such elements that are located in one logic level of the utilized network architecture. By contrast, a lower-ranking network element is at least one hierarchical level below the higher-ranking element.
The operating system of the present invention controls a data and communication network consisting of various lower-ranking physical base networks. These base networks consist of network elements which provide different network (basic) services and network functions and can be controlled with system-specific calls.
Accordingly, there exist corresponding higher-ranking network elements that are equipped with specific operating system components and which execute basic functions that are independent of the physical subnetworks, such as accessing the physical base network, distributing calls of basic services, and converting the calls into the corresponding system-specific formats (providing the interfaces). These higher-ranking network elements can be part of the existing physical networks or stand-alone network elements.
The interfaces that enable the accessing of the physical base services can be laid open on the system-independent side, such as in the form of a standardization of a unified access format, for example.
This structure of the data and communication networks distributes the control of the basic services, network services and value-added services to the network elements in that information needed for interworking is exchanged. The network elements can either be identical in structure or different.
In this way, the problems of centralized control such as those that exist in an intelligent network (reliability, availability, xe2x80x9cbottleneckxe2x80x9d, error tolerance) are avoided.
Furthermore, an integration of different basic services of different physical base networks is possible.
The insertion and removal of individual network elements or whole physical base networks should be possible without any problems. Therefore, the information that is stored in the network elements (in particular in the higher-ranking network elements) is regularly updated and distributed to the neighboring network elements in order to make it possible to coordinate the function and service calls. This relates not only to the insertion of new services and base networks (independent of manufacturer), but also to the modification of already existing services and base networks. This mode of functioning creates a flexibility that is a precondition for introducing ever new value-added services (particularly those consisting of combinations of basic services of different physical base networks).
For the distributed execution of functions, the distributed operating system can control the network elements according to the client-server principle. Each network element should be able to work either as client or server, which is guaranteed by a uniform structure of each network element.
This makes it possible to transport function and service calls through the network and to have the calls processed at the most suitable network element. It is also possible that network services and functions may be executed by several network elements.
An application call can be executed in a distributed manner. It may be necessary for this purpose to divide it into subfunctions or subservices in advance.
The operating system controls the execution of these functions and services in that the relevant network elements receive the function and service calls via the defined system-independent open interfaces and convert them into system-specific calls. This makes individual functions available in such a way that integrated value-added services can be formed from basic services and functions of different physical base networks.
The operating system controls the execution of the service and function calls on the basis of information present in the network elements about which network element possesses which functionalities. The calls are routed to the corresponding appropriate network elements.
Various principles of path selection methods can be individually or jointly applied to this end. Examples include
dynamic routing (i.e. the information that is distributed to the network elements about the capabilities of the network elements is continuously updated in that messages are generated by network elements that are affected by modifications, which messages are distributed in the network and evaluated by the other network elements)
distributed routing (i.e. any element located in the network can make path selection decisions (no central control of the path selection)
multi-path routing (i.e. a distribution of the function and service calls via several paths, so that, in part, it is also possible to initiate a multiple execution of the call in different network elements. This increases the throughput (the fastest path), the redundancy, and, hence, the error tolerance)
hierarchical routing (i.e. an application call is first split into subfunction and subservice calls and is forwarded (potentially even via several abstraction levels), and only then into basic functions and services which can be executed)
link state routing (i.e. only that information which describes the modifications to network element capabilities is sent for the purpose of path selection (network mapping). This reduces the data flow which is necessary for administrative purposes)
function class routing (i.e. calls are prioritized with regard to their processing, for instance according to permitted time delay, required throughput and required availability, for example
In accordance with an embodiment of the present invention, the operating system can be constructed in 3 layers:
an application layer
a service development layer,
a network element functionality layer.
The different layers realize different tasks and are active in the network elements in different ways depending on whether a client or server role is assumed, although they occur the same way in all network elements.
The application layer provides the applications. This layer is active only in the case where the network element is acting as a client.
The middle layer (server development layer) has the following tasks:
converting application calls via corresponding interfaces into function and service calls, potentially with the aid of APIs (Application Programming Interfaces);
forwarding the function and service calls to appropriate network elements for further processing according to the information stored in the network elements relating to the network, in a suitable manner, namely with the required parameters in the system-specific format of the physical base network;
resource and performance management;
billing and rating (processing specific data via connections, such as AMA data);
security;
error management (detecting, processing, evaluating errors);
managing the required information (e.g. in data bases); and
transaction monitoring.
The operating system can control every network element either as client or as server, depending on whether the network element is a requesting element or an executing element. The service development layer can also be operated as client or server depending on the function being assumed.
When the network element is operating in the request mode (as a client), the following functionalities are active:
operation of an interface (interface manager), which accepts system-independent service and function calls and translates them into corresponding system-dependent calls (base-network-dependent) in order to then forward them to the appropriate system-specific transport mechanisms, with, the information that is needed for the path selection of the function and service calls maintained, with
providing commonly needed basic services (e.g. address conversion, data replication, database management); and
transport mechanisms for readying the connection to the network elements and to the system-specific call format needed therefor.
There are various types of transport mechanisms, including
server-specific transport mechanisms, dependent on the network elements of the underlying base network; and
server-independent (default) transport mechanisms for communication between neighboring network elements, such as within the application layer, for example
If the interface manager, with the aid of the information available to it, identifies that the network element in which it resides is directly connected to the base network that is responsible for executing the call, then this function call is converted into the system-specific format of the corresponding base network and is transferred to the connected network element of the base network for execution. The dynamic updating of the information about capabilities of a network is ensured in that when new basic functions and services are available, each element (server) in the network updates information for the updating of the server-specific transport mechanisms and distributes it to other network elements (clients), on the basis of which the interfaces and further information (such as routing tables) in these network elements are modified.
If the network element in which the interface manager resides is not directly connected to the element that is responsible for executing the call, this call is transferred to a standard transport mechanism. This then ensures that the function call is appropriately routed to network elements that receive and execute these calls as server or that, as clients, ensure their processing.
When the network element is currently operating in execute mode (as a server), the following functionalities are active in the service development layer:
with a firewall;
an access check;
a filter for monitoring and controlling received calls and messages.
The network functionality contains the following tasks for executing the function and service calls:
connection control;
call control;
user programs;
feature control;
switching;
path selection;
transport.
The network operating system can structure the overall telecommunication network into several layers (i.e. the functional network domains) These network domains define the type and manner of the application calls in subfunction and subservice calls and so on. This principle makes possible the above mentioned hierarchical routing.
Since the information about the capabilities of the network elements is exchanged in hierarchical layers, each network element only requires knowledge about the functional capabilities of a limited number of network elements. Depending on the requirements with respect to processing duration and speed of calls, it is possible for different network elements (i.e. possible servers) to be selected in the network element (i.e. functioning as client), and the server-specific transport mechanisms connected to these can be addressed in order to optimize processing times and network throughput times. The functional domains can be oriented to the existing base networks, for example, or to various organizational structures or network operators.
In turn , the network domains can consist of core network elements and standard network elements. All network elements must contain information (for the path selection) about which function and service classes can be executed in particular domains.
The core network elements are essentially responsible for executing the application requests and service and function calls. Here, circumstances should be avoided under which calls can no longer be executed with the requisite quality of service (bandwidth, time, and so on). For this reason, application requests and service and function calls can be prioritized and allocated to the various executing network elements corresponding to the existing resources. For the optimal functioning of these network elements, a dynamic updating of the path selection tables is necessary, and, thus, a continuous updating of the type, scope and location of the network functions, services and resources that are available in the network.
Standard network elements, on the other hand, specifically perceive functions of detection and classification as well as the path selection in those service and function calls that could not be executed by a core network element. The following mechanisms are needed for handling calls, for example:
forwarding the call to a network domain having a corresponding service and function class; an
forwarding the call to a network element having a corresponding service and function class;
forwarding the call to a network element or a network domain of which it is known that similar services and functions or service and function classes are executed there; and
rejecting calls.
Standard network elements also perceive functions of access control for network domains, for instance in cases in which particular limits exist with respect to the execution of applications, functions and services. The calls are permitted, rejected or provided with a priority.
Additional advantages and novel features of the invention will be set forth, in part, in the description that follows and, in part, will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.